Cost and size reduction is driving packaging industry to new measures and approaches. Wafer level packaging is one approach which the packaging industry is looking into for size and cost reduction. Since wafer level packaging is a batch process and is almost a true chip size package, cost and real estate can be reduced. A further reduction in size may be achieved by integrating different devices into a single package.
Wafer level packaging may also be used for Micro-Electro-Mechanical Systems (MEMS) devices to meet the requirements of size, cost, hermeticity and vacuum. For MEMS devices which have moving parts or suspended beams, air inside the MEMS device package may dampen the moving parts. Therefore, there is a need to maintain a vacuum within the MEMS device package in order to prevent damping of the moving parts or suspended beams. Further vacuum is a poor conductor of heat and this may be used for MEMS device package to allow for high thermal isolation or stability.
Therefore, there is a need for a wafer level packing for MEMS device which may provide good vacuum reliability within the MEMS device package.